JP4727238B2 - Optical member pressure-sensitive adhesive composition, optical member pressure-sensitive adhesive layer, pressure-sensitive adhesive optical member, and image display device - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive composition for optical members. Moreover, this invention relates to the adhesive layer for optical members formed with the said adhesive composition for optical members. Furthermore, the present invention relates to an adhesive optical member having the adhesive layer, a liquid crystal display device using the adhesive optical member, an organic EL display device, and an image display device such as a PDP. Examples of the optical member include a polarizing plate, a retardation plate, an optical compensation film, a brightness enhancement film, and those in which these are laminated.

  The pressure-sensitive adhesive layer used for an optical member is required to have a high level of thickness and surface uniformity. Therefore, the coating is carried out by lowering the polymer concentration to reduce the viscosity of the polymer composition. However, the actual situation is to reduce the amount of organic solvent used as much as possible in consideration of the environment.

  As methods that do not use an organic solvent, there are emulsion adhesives and UV polymerization type adhesives, but they have not yet been used for optical members such as water resistance problems and uniformity of thickness.

  As a method for preventing the viscosity of the polymer solution from increasing even when the polymer concentration is increased, a method for reducing the molecular weight of the polymer can be mentioned. However, optical members used in liquid crystal display devices, such as polarizing plates and retardation plates, are attached to liquid crystal cells via an adhesive, but the expansion and contraction of optical members under heating and humidification conditions. Therefore, after sticking, the floating and peeling accompanying it are likely to occur. When the molecular weight of the polymer is small, it is difficult to reduce the molecular weight of the polymer because it tends to float and peel off under heating and humidification conditions.

  Polarized light containing several specific (meth) acrylic polymers and a cross-linking agent for the purpose of maintaining excellent adhesion even under high temperature and high humidity conditions and preventing the occurrence of foaming and peeling due to dimensional changes. An adhesive composition for a plate is disclosed (Patent Document 1).

  Also disclosed is a pressure-sensitive adhesive composition in which a curing agent and a specific silane compound are blended in an acrylic resin for the purpose of reducing the temporal change of cohesive force and adhesive force even under high temperature or high temperature and high humidity. (Patent Document 2).

However, these conventional pressure-sensitive adhesive compositions cannot satisfy both the reduction in the amount of organic solvent used and the high surface uniformity of the formed pressure-sensitive adhesive layer.
JP 2003-49141 A JP-A-8-199131

  The present invention is a pressure-sensitive adhesive for optical members that has good coating properties due to low viscosity, can reduce the amount of organic solvent used, and can form a pressure-sensitive adhesive layer with excellent durability and high surface uniformity. An object is to provide a composition. Moreover, an object of this invention is to provide the adhesive layer for optical members formed with this adhesive composition for optical members. Furthermore, an object of this invention is to provide the adhesive optical member which has this adhesive layer, and to provide the image display apparatus using this adhesive optical member.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have found that the above-described object can be achieved by the following pressure-sensitive adhesive composition for optical members, and have completed the present invention.

  That is, the present invention provides a (meth) acrylic polymer, a hydrocarbon solvent having 6 to 9 carbon atoms (A), and a boiling point higher than that of the hydrocarbon solvent and (meth) acrylic than that of the hydrocarbon solvent. A high-boiling high-solubility solvent (B) having a high polymer solubility, the content of the hydrocarbon solvent (A) is 20 to 60% by weight of the total organic solvent, and the high-boiling high Ratio of the content (% by weight) of the hydrocarbon solvent (A) to the content (% by weight) of the soluble solvent (B) (high boiling point high solubility solvent (B) / hydrocarbon solvent (A)) Relates to a pressure-sensitive adhesive composition for an optical member having a thickness of 0.05 to 4.

  The pressure-sensitive adhesive composition for optical members of the present invention has a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition for optical members by using the two kinds of solvents in combination as a solvent for dissolving the (meth) acrylic polymer. Even after the optical member is bonded to a liquid crystal cell or the like, the pressure-sensitive adhesive layer can be prevented from being lifted or peeled even when exposed to heating conditions or humidification conditions. Furthermore, since the viscosity is small, the coating property is good, and the surface uniformity of the formed pressure-sensitive adhesive layer can be kept high while reducing the content of the organic solvent in the pressure-sensitive adhesive composition.

  Thus, although the reason why these effects are manifested by using the two kinds of solvents in combination is not clear, the following reasons can be considered. By using the hydrocarbon solvent (A), the polymer domain of the (meth) acrylic polymer can be contracted. Therefore, the viscosity of the pressure-sensitive adhesive composition can be reduced, but when only the solvent is used, the surface uniformity of the pressure-sensitive adhesive layer is significantly reduced due to precipitation of a polymer during coating and drying, When the polymer is precipitated, the entanglement between the molecular chains becomes insufficient, and the pressure-sensitive adhesive layer easily floats or peels off under heating or humidification conditions. However, by using the high-boiling high-solubility solvent (B) in combination, the high-boiling high-solubility solvent (B) is delayed from the hydrocarbon solvent (A) at the time of coating and drying the pressure-sensitive adhesive composition. Since it volatilizes, it can suppress effectively that the polymer in an adhesive composition precipitates, and it is thought that the surface uniformity of the adhesive layer formed maintains high. In addition, since the high-boiling and high-solubility solvent (B) has high polymer solubility, the polymer domain expands, entanglement between molecular chains increases, and cross-linking between molecular chains also proceeds uniformly. Therefore, it is considered that the pressure-sensitive adhesive layer can be prevented from being lifted or peeled even when exposed to heating conditions or humidification conditions.

  In the present invention, the content of the hydrocarbon solvent (A) needs to be 20 to 60% by weight of the total organic solvent. If it is less than 20% by weight, the effect of reducing the viscosity of the pressure-sensitive adhesive composition is small, and it becomes difficult to reduce the amount of organic solvent used. On the other hand, when the amount exceeds 60% by weight, the (meth) acrylic polymer is precipitated during coating and drying, and the surface uniformity of the pressure-sensitive adhesive layer is remarkably reduced, or the polymer is precipitated, thereby entanglement between molecular chains. Becomes insufficient, and the pressure-sensitive adhesive layer easily floats or peels off under heating or humidification conditions.

  In the present invention, the ratio of the content (% by weight) of the hydrocarbon solvent (A) to the content (% by weight) of the high boiling point high solubility solvent (B) (the high boiling point high solubility solvent (B) / The hydrocarbon solvent (A)) needs to be 0.05-4. When the ratio is less than 0.05, when the pressure-sensitive adhesive composition is applied and dried, the polymer precipitates and the surface uniformity of the pressure-sensitive adhesive layer is remarkably reduced, or the polymer is precipitated to cause intermolecular chains. The entanglement of the adhesive layer becomes insufficient, and the pressure-sensitive adhesive layer is lifted or peeled off under heating or humidification conditions. On the other hand, when the ratio exceeds 4, it is difficult to sufficiently dry and remove the solvent, and the adhesive properties such as durability are deteriorated.

  In the present invention, the (meth) acrylic polymer contains 60% by weight or more of an alkyl acrylate having an alkyl group having 2 to 4 carbon atoms as a monomer, has a weight average molecular weight of 1,500,000 or more, and The content of the polymer component having a molecular weight of 100,000 or less is preferably 20% by weight or less. The (meth) acrylic polymer preferably further contains 0.2 to 7% by weight of an unsaturated carboxylic acid as a monomer.

  The pressure-sensitive adhesive composition for optical members of the present invention preferably contains 0.01 to 1 part by weight of a silane coupling agent with respect to 100 parts by weight of the (meth) acrylic polymer. Moreover, it is preferable to contain 0.1-5 weight part of crosslinking agents with respect to 100 weight part of (meth) acrylic-type polymers. The pressure-sensitive adhesive layer having a cross-linked structure formed by a pressure-sensitive adhesive composition containing a silane coupling agent or a cross-linking agent passes a long time such as passing through various steps after the optical member is attached to the liquid crystal cell, Even when stored in a high temperature and high humidity state, peeling, floating, foaming and the like are suppressed in the bonded state, and the durability is excellent.

  The present invention relates to an optical member pressure-sensitive adhesive layer formed from the optical member pressure-sensitive adhesive composition.

  The present invention also relates to an adhesive optical member having the optical member pressure-sensitive adhesive layer on one or both surfaces of the optical member.

  Furthermore, the present invention relates to an image display device using at least one of the adhesive optical members.

  The pressure-sensitive adhesive composition for an optical member of the present invention comprises a (meth) acrylic polymer, a hydrocarbon solvent having 6 to 9 carbon atoms (A), and a boiling point higher than that of the hydrocarbon solvent and the hydrocarbon solvent. The main component is a high-boiling high-solubility solvent (B) in which the solubility of the (meth) acrylic polymer is higher. In the present invention, the (meth) acrylic polymer refers to an acrylic polymer and / or a methacrylic polymer. (Meta) has the same meaning.

  The (meth) acrylic polymer used in the present invention is not particularly limited, but a homopolymer or copolymer of an alkyl (meth) acrylate having an alkyl group having 2 to 4 carbon atoms from the viewpoint of low glass transition point and elastic modulus, Or it is preferable that they are mixtures. It is more preferable that the alkyl group has 3 to 4 carbon atoms. The alkyl group can be either linear or branched.

  The (meth) acrylic polymer preferably contains 60% by weight or more, more preferably 70% by weight of alkyl (meth) acrylate having a C2-C4 alkyl group as a monomer unit from the viewpoint of adhesive properties. % Or more.

  The (meth) acrylic polymer may be a copolymer of an unsaturated carboxylic acid in order to adjust the adhesive properties.

  Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, itaconic acid, maleic acid and the like. These anhydrides can also be used. Of these, acrylic acid and methacrylic acid are particularly preferably used.

  The (meth) acrylic polymer preferably contains 0.2 to 7% by weight of unsaturated carboxylic acid as a monomer unit, more preferably 0.5 to 5% by weight. When the content of the unsaturated carboxylic acid is less than 0.2% by weight, the durability is lowered, and when it exceeds 7% by weight, the adhesive force to the liquid crystal cell becomes too large or too hard.

  The (meth) acrylic polymer may contain a monomer other than the above. Examples of other monomers include alkyl (meth) acrylates having an alkyl group having 5 or more carbon atoms such as pentyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, and the like; 2 Monomers having a hydroxyl group such as hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, hydroxyhexyl (meth) acrylate, N-methylol (meth) acrylamide; glycidyl (meth) acrylate Monomers containing an epoxy group such as: (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, (meth) acryloylmorpholine, (meth) acetonitrile, vinyl Rupiroridon, N- cyclohexyl maleimide, itaconimide, N, monomers having N- dimethylaminoethyl (meth) N elements acrylamide and the like. Furthermore, vinyl acetate, styrene, etc. can also be used. These monomers can be used alone or in combination of two or more.

  The weight average molecular weight (measured by GPC) of the (meth) acrylic polymer is preferably 1.5 million or more, more preferably 2 million or more. When the weight average molecular weight is less than 1,500,000, the durability of the pressure-sensitive adhesive layer tends to be poor. In the (meth) acrylic polymer, the proportion of the polymer component having a molecular weight of 100,000 or less is preferably 20% by weight or less, more preferably 10% by weight or less. In the present invention, since the entanglement of the polymer chain is reduced by using the hydrocarbon solvent (A) having 6 to 9 carbon atoms, if there are many low molecular weight polymer components, the crosslinkability between the polymer molecular chains is very high. Deteriorate. Therefore, the lower the low molecular weight polymer component, the better.

  For the production of the (meth) acrylic polymer, known radical polymerization methods such as solution polymerization, bulk polymerization, and emulsion polymerization can be selected as appropriate, but radical polymerization using an organic solvent is preferred. A polymerization method using water such as emulsion polymerization is economically disadvantageous because it is necessary to dry the water once and then mix it with the solvent of the present invention. As the radical polymerization initiator, various known azo and peroxide initiators can be used. For example, in solution polymerization, a polymerization initiator such as azobisisobutyronitrile is used in an amount of about 0.01 to 0.2 parts by weight with respect to 100 parts by weight of the total amount of monomers. As the polymerization solvent, for example, a good solvent such as ethyl acetate or toluene is used. The reaction is usually carried out at about 50 to 70 ° C. for about 8 to 15 hours under an inert gas stream such as nitrogen.

  In the present invention, as the organic solvent, the hydrocarbon solvent (A) having 6 to 9 carbon atoms, and the solubility of the (meth) acrylic polymer is higher than the hydrocarbon solvent and higher than the hydrocarbon solvent. It is necessary to use a high-boiling and high-solubility solvent (B) having a high value.

  The hydrocarbon solvent (A) preferably has 6 to 8 carbon atoms. A hydrocarbon solvent having 5 or less carbon atoms has a low boiling point and thus lacks coating stability. On the other hand, since the hydrocarbon solvent having 10 or more carbon atoms has a boiling point that is too high, the solvent remains in the pressure-sensitive adhesive layer after drying, and the adhesive properties such as durability tend to decrease.

  The hydrocarbon solvent (A) having 6 to 9 carbon atoms may be any of linear, branched, and cyclic hydrocarbons, specifically, 3-methylpentane, normal hexane, 2,4 -Dimethylpentane, 2,2,3-trimethylbutane, 3,3-dimethylpentane, 2-methylhexane, 2,3-dimethylpentane, 3-methylhexane, normal heptane, cyclohexane, methylcyclohexane, 2, 2-dimethyl hexane, 2,3-dimethyl hexane, 2,5-dimethyl hexane, 2,4-dimethyl hexane, 3,3-dimethyl hexane, 3,4-dimethyl hexane, 2,3, 4-trimethylpentane, 2,3,3-trimethylpentane, 2-methyl-3-ethylpentane, 2-methylheptane, 3-methylheptane, 4-methylheptane, 2,2, - hexane trimethyl, normal octane, cyclooctane, nonane, and cyclononane and the like. These may be used alone or in combination of two or more. Moreover, you may use the solvent containing these, Specifically, Cactus solvent (made by Japan Energy) is mentioned.

  The content of the hydrocarbon solvent (A) in the pressure-sensitive adhesive composition for optical members is 20 to 60% by weight, preferably 35 to 55% by weight, more preferably 40 to 40% by weight of the total organic solvent to be used. 50% by weight.

The high boiling point high solubility solvent (B) may be an organic solvent having a higher boiling point than the hydrocarbon solvent (A) and a higher solubility of the (meth) acrylic polymer than the hydrocarbon solvent (A). Although it will not restrict | limit in particular, It is preferable that a boiling point is 5 degreeC or more higher than a hydrocarbon type solvent (A). The high-boiling and high-solubility solvent (B) includes a solubility parameter θ1 [(cal / cm ³ ) ^1/2 ] of the high-boiling and high-solubility solvent (B) and a solubility parameter θ2 [(()) of the (meth) acrylic polymer. cal / cm ³ ) ^1/2 ] is preferably selected such that Δθ (Δθ = θ1−θ2) is 0.8 or less, more preferably 0.5 or less, particularly preferably 0.8. 3 or less. Solubility parameters are described, for example, in Polymer Handbook 3rd edition published by Wiley Interscience.

  Examples of the high-boiling and high-solubility solvent (B) used in the present invention include aromatic hydrocarbon solvents such as toluene and xylene; aliphatic carboxylic acid ester solvents such as ethyl acetate and butyl acetate; methyl ethyl ketone and ethyl butyl Examples thereof include ketone solvents such as ketones. As the high boiling point high solubility solvent (B), it is necessary to appropriately select a solvent satisfying the above conditions in relation to the hydrocarbon solvent (A).

  In the present invention, the ratio of the content (wt%) of the hydrocarbon solvent (A) to the content (wt%) of the high boiling high solubility solvent (B) (high boiling high solubility solvent (B) / carbonization). The hydrogen-based solvent (A)) is 0.05 to 4, preferably 0.05 to 1.86, more preferably 0.2 to 0.75.

  The pressure-sensitive adhesive composition for optical members of the present invention preferably contains a silane coupling agent or a crosslinking agent.

  As the silane coupling agent, those conventionally known can be used without particular limitation. For example, epoxy group-containing silane coupling agents such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane; 3-amino Amino group-containing silane coupling agents such as propyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine ; (Meth) acryl group-containing silane coupling agents such as 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane; isocyanate group-containing silane coupling agents such as 3-isocyanatopropyltriethoxysilane Is .

  It is preferable that the addition amount of a silane coupling agent is 0.01-1 weight part with respect to 100 weight part of (meth) acrylic-type polymers, More preferably, it is 0.02-0.6 weight part. If the addition amount of the silane coupling agent exceeds 1 part by weight, the adhesive strength to the liquid crystal cell increases and the removability is inferior.

  The crosslinking agent is a polyfunctional compound that can react with the (meth) acrylic polymer to form a crosslinked structure. Examples of the crosslinking agent include polyisocyanate compounds obtained by adding diisocyanate compounds such as tolylene diisocyanate and diphenylmethane diisocyanate to various polyols, epoxy compounds, aziridine compounds, melamine compounds, metal salts, metal chelate compounds, and the like. Of these, polyisocyanate compounds are preferably used. In particular, when a hydroxyl group is introduced into a (meth) acrylic polymer by copolymerizing a hydroxyl group-containing monomer such as 2-hydroxyethyl acrylate during the production of the (meth) acrylic polymer, a polyisocyanate compound is used. Thus, it is preferable to form a crosslinked structure.

  The addition amount of the crosslinking agent is preferably 0.01 to 5 parts by weight, more preferably 0.02 to 2 parts by weight, with respect to 100 parts by weight of the (meth) acrylic polymer. When the addition amount of the crosslinking agent is less than 0.01% by weight, the crosslinked structure is not sufficiently formed, so that the durability tends to be inferior, and when it exceeds 5% by weight, the stress relaxation property tends to be inferior.

  The pressure-sensitive adhesive composition for optical members of the present invention can contain a polymerization initiator, an ultraviolet absorber, an anti-aging agent, a softening agent, a dye, a pigment, a filler, and the like, if necessary.

  The pressure-sensitive adhesive optical member of the present invention is obtained by forming a pressure-sensitive adhesive layer on one side or both sides of the optical member with the pressure-sensitive adhesive composition for optical members.

  The method for forming the pressure-sensitive adhesive layer on the optical member is not particularly limited. 1) The pressure-sensitive adhesive composition is coated on a release-treated support (release sheet) and dried (if necessary, a crosslinking reaction) to form a pressure-sensitive adhesive layer. And a method of forming the pressure-sensitive adhesive layer by applying the pressure-sensitive adhesive composition directly to the optical member and drying (crosslinking reaction if necessary).

  As an application method of the pressure-sensitive adhesive composition, any application method such as a roll coater such as a reverse coater or a gravure coater, a curtain coater, a lip coater, or a die coater can be adopted. Usually, the thickness of a coating film is 2-500 micrometers, Preferably it is 5-100 micrometers.

  As a material for the support (release sheet), suitable materials such as paper, synthetic resin films such as polyethylene, polypropylene, polyethylene terephthalate, rubber sheets, paper, cloth, nonwoven fabric, nets, foam sheets, metal foils, laminates thereof, and the like Examples include thin leaves. The surface of the support may be subjected to a release treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment as necessary in order to enhance the peelability from the pressure-sensitive adhesive layer.

  When the pressure-sensitive adhesive layer is exposed on the surface of the pressure-sensitive adhesive optical member, it is preferably protected with a release-treated sheet until it is put to practical use.

  An optical member used for forming a liquid crystal display device or the like is used, and the type thereof is not particularly limited. For example, the optical member includes a polarizing plate. A polarizing plate having a transparent protective film on one or both sides of a polarizer is generally used.

  The polarizer is not particularly limited, and various types can be used. Examples of the polarizer include hydrophilic polymer films such as polyvinyl alcohol film, partially formalized polyvinyl alcohol film, and ethylene / vinyl acetate copolymer partially saponified film, and two colors such as iodine and dichroic dye. Examples thereof include polyene-based oriented films such as those obtained by adsorbing volatile substances and uniaxially stretched, polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products. Among these, a polarizer composed of a polyvinyl alcohol film and a dichroic material such as iodine is preferable. The thickness of these polarizers is not particularly limited, but is generally about 5 to 80 μm.

  A polarizer obtained by dyeing a polyvinyl alcohol film with iodine and uniaxially stretching it can be produced, for example, by dyeing polyvinyl alcohol in an aqueous solution of iodine and stretching it 3 to 7 times the original length. If necessary, it can be immersed in an aqueous solution such as potassium iodide which may contain boric acid, zinc sulfate, zinc chloride and the like. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. In addition to washing the polyvinyl alcohol film surface with dirt and anti-blocking agents by washing the polyvinyl alcohol film with water, it also has the effect of preventing unevenness such as uneven coloring by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, or may be performed while dyeing, or may be performed with dyeing after iodine. The film can be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

  As a material for forming the transparent protective film provided on one side or both sides of the polarizer, a material excellent in transparency, mechanical strength, thermal stability, moisture shielding property, isotropy and the like is preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, styrene such as polystyrene and acrylonitrile / styrene copolymer (AS resin) -Based polymer, polycarbonate-based polymer and the like. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above Polymer blends and the like are also examples of polymers that form the transparent protective film. The transparent protective film can also be formed as a cured layer of thermosetting or ultraviolet curable resin such as acrylic, urethane, acrylurethane, epoxy, and silicone.

  Moreover, the polymer film described in JP-A-2001-343529 (WO01 / 37007), for example, (A) a thermoplastic resin having a substituted and / or unsubstituted imide group in the side chain, and (B) a substitution in the side chain And / or a resin composition containing an unsubstituted phenyl and a thermoplastic resin having a nitrile group. A specific example is a film of a resin composition containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer. As the film, a film made of a mixed extruded product of the resin composition or the like can be used.

  Although the thickness of a protective film can be determined suitably, generally it is about 1-500 micrometers from points, such as workability | operativity, such as intensity | strength and handleability, and thin layer property. 1-300 micrometers is especially preferable, and 5-200 micrometers is more preferable.

  Moreover, it is preferable that a protective film has as little color as possible. Therefore, Rth = (nx−nz) · d (where nx is the refractive index in the slow axis direction in the film plane, nz is the refractive index in the film thickness direction, and d is the film thickness). A protective film having a direction retardation value of −90 nm to +75 nm is preferably used. By using a film having a thickness direction retardation value (Rth) of −90 nm to +75 nm, the coloring (optical coloring) of the polarizing plate caused by the protective film can be almost eliminated. The thickness direction retardation value (Rth) is more preferably −80 nm to +60 nm, and particularly preferably −70 nm to +45 nm.

  As the protective film, a cellulose polymer such as triacetyl cellulose is preferable from the viewpoints of polarization characteristics and durability. A triacetyl cellulose film is particularly preferable. In addition, when providing a protective film in the both sides of a polarizer, the protective film which consists of the same polymer material may be used by the front and back, and the protective film which consists of a different polymer material etc. may be used. The polarizer and the protective film are usually in close contact with each other through an aqueous adhesive or the like. Examples of the water-based adhesive include an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, a vinyl-based latex, a water-based polyurethane, and a water-based polyester.

  The surface of the transparent protective film to which the polarizer is not adhered may be subjected to a hard coat layer, an antireflection treatment, an antisticking treatment, or a treatment for diffusion or antiglare.

  The hard coat treatment is applied for the purpose of preventing scratches on the surface of the polarizing plate. For example, a transparent protective film with a cured film excellent in hardness, sliding properties, etc. by an appropriate ultraviolet curable resin such as acrylic or silicone is used. It can be formed by a method of adding to the surface of the film. The antireflection treatment is performed for the purpose of preventing reflection of external light on the surface of the polarizing plate, and can be achieved by forming an antireflection film or the like according to the conventional art. Further, the anti-sticking treatment is performed for the purpose of preventing adhesion with an adjacent layer.

  The anti-glare treatment is applied for the purpose of preventing the outside light from being reflected on the surface of the polarizing plate and obstructing the visibility of the light transmitted through the polarizing plate. For example, the surface is roughened by a sandblasting method or an embossing method. It can be formed by imparting a fine concavo-convex structure to the surface of the transparent protective film by an appropriate method such as a blending method of transparent fine particles. The fine particles to be included in the formation of the surface fine concavo-convex structure are, for example, conductive materials made of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide or the like having an average particle diameter of 0.5 to 50 μm. In some cases, transparent fine particles such as inorganic fine particles, organic fine particles composed of a crosslinked or uncrosslinked polymer, and the like are used. When forming a surface fine uneven structure, the amount of fine particles used is generally about 2 to 50 parts by weight, preferably 5 to 25 parts by weight, based on 100 parts by weight of the transparent resin forming the surface fine uneven structure. The antiglare layer may also serve as a diffusion layer (viewing angle expanding function or the like) for diffusing the light transmitted through the polarizing plate to expand the viewing angle.

  The antireflection layer, antisticking layer, diffusion layer, antiglare layer, and the like can be provided on the transparent protective film itself, or can be provided separately from the transparent protective film as an optical layer.

  The optical member of the present invention includes, for example, a liquid crystal display device such as a reflecting plate, a transflective plate, a retardation plate (including wavelength plates such as 1/2 and 1/4), a viewing angle compensation film, and a brightness enhancement film. What becomes an optical layer which may be used for formation is mention | raise | lifted. These can be used alone as the optical member of the present invention, and can be laminated on the polarizing plate for practical use and used in one or more layers.

  In particular, a reflective polarizing plate or a semi-transmissive polarizing plate in which a polarizing plate is further laminated with a reflecting plate or a semi-transmissive reflecting plate, an elliptical polarizing plate or a circular polarizing plate in which a retardation plate is further laminated on a polarizing plate, a polarizing plate A wide viewing angle polarizing plate in which a viewing angle compensation film is further laminated on a plate, or a polarizing plate in which a brightness enhancement film is further laminated on a polarizing plate is preferable.

  A reflective polarizing plate is a polarizing plate provided with a reflective layer, and is used to form a liquid crystal display device or the like that reflects incident light from the viewing side (display side). Such a light source can be omitted, and the liquid crystal display device can be easily thinned. The reflective polarizing plate can be formed by an appropriate method such as a method in which a reflective layer made of metal or the like is attached to one surface of the polarizing plate via a transparent protective layer or the like as necessary.

  Specific examples of the reflective polarizing plate include those in which a reflective layer is formed by attaching a foil or a vapor deposition film made of a reflective metal such as aluminum on one side of a transparent protective film matted as necessary. Moreover, the transparent protective film contains fine particles so as to have a surface fine concavo-convex structure and a reflective layer having a fine concavo-convex structure thereon. The reflective layer having the fine concavo-convex structure has an advantage that incident light is diffused by irregular reflection to prevent directivity and glaring appearance and to suppress unevenness in brightness and darkness. The transparent protective film containing fine particles also has an advantage that incident light and its reflected light are diffused when passing through it, and light and dark unevenness can be further suppressed. The reflective layer of the fine concavo-convex structure reflecting the surface fine concavo-convex structure of the transparent protective film is formed by transparent the metal by an appropriate method such as a vapor deposition method such as a vacuum vapor deposition method, an ion plating method, a sputtering method, or a plating method. It can be performed by a method of directly attaching to the surface of the protective layer.

  Instead of the method of directly applying the reflecting plate to the transparent protective film of the polarizing plate, the reflecting plate can be used as a reflecting sheet provided with a reflecting layer on an appropriate film according to the transparent film. Since the reflective layer is usually made of metal, the usage form in which the reflective surface is covered with a transparent protective film, a polarizing plate or the like is used to prevent the reflectance from being lowered due to oxidation, and thus to maintain the initial reflectance for a long time. In addition, it is more preferable to avoid a separate attachment of the protective layer.

  The semi-transmissive polarizing plate can be obtained by using a semi-transmissive reflective layer such as a half mirror that reflects and transmits light with the reflective layer. A transflective polarizing plate is usually provided on the back side of a liquid crystal cell, and displays an image by reflecting incident light from the viewing side (display side) when a liquid crystal display device is used in a relatively bright atmosphere. In a relatively dark atmosphere, a liquid crystal display device or the like that displays an image using a built-in light source such as a backlight built in the back side of the transflective polarizing plate can be formed. In other words, the transflective polarizing plate is useful for forming a liquid crystal display device of a type that can save energy of using a light source such as a backlight in a bright atmosphere and can be used with a built-in light source even in a relatively dark atmosphere. It is.

  An elliptically polarizing plate or a circularly polarizing plate in which a retardation plate is further laminated on a polarizing plate will be described. A phase difference plate or the like is used when changing linearly polarized light to elliptically polarized light or circularly polarized light, changing elliptically polarized light or circularly polarized light to linearly polarized light, or changing the polarization direction of linearly polarized light. In particular, a so-called quarter-wave plate (also referred to as a λ / 4 plate) is used as a retardation plate that changes linearly polarized light into circularly polarized light or changes circularly polarized light into linearly polarized light. A half-wave plate (also referred to as a λ / 2 plate) is usually used when changing the polarization direction of linearly polarized light.

  The elliptically polarizing plate is effectively used for black and white display without the above color by compensating (preventing) the coloration (blue or yellow) generated by the birefringence of the liquid crystal layer of the super twist nematic (STN) type liquid crystal display device. It is done. Further, the one in which the three-dimensional refractive index is controlled is preferable because it can compensate (prevent) coloring that occurs when the screen of the liquid crystal display device is viewed from an oblique direction. The circularly polarizing plate is effectively used, for example, when adjusting the color tone of an image of a reflective liquid crystal display device in which an image is displayed in color, and also has an antireflection function.

  Examples of the retardation plate include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, a liquid crystal polymer alignment film, and a liquid crystal polymer alignment layer supported by a film. The thickness of the retardation plate is not particularly limited, but is generally about 20 to 150 μm.

  Examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polycarbonate, polyarylate, polysulfone, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, Polyphenylene sulfide, polyphenylene oxide, polyallylsulfone, polyvinyl alcohol, polyamide, polyimide, polyolefin, polyvinyl chloride, cellulose polymer, norbornene resin, or binary, ternary various copolymers, graft copolymers Examples thereof include polymers and blends. These polymer materials become oriented products (stretched films) by stretching or the like.

  Examples of the liquid crystalline polymer include various main chain types and side chain types in which a conjugated linear atomic group (mesogen) imparting liquid crystal alignment is introduced into the main chain or side chain of the polymer. It is done. Specific examples of the main chain type liquid crystalline polymer include, for example, a nematic alignment polyester liquid crystalline polymer, a discotic polymer, and a cholesteric polymer having a structure in which a mesogen group is bonded to a spacer portion that imparts flexibility. . Specific examples of the side chain type liquid crystalline polymer include polysiloxane, polyacrylate, polymethacrylate, or polymalonate as a main chain skeleton, and a nematic alignment imparting paraffin through a spacer portion composed of a conjugated atomic group as a side chain. Examples thereof include those having a mesogen moiety composed of a substituted cyclic compound unit. These liquid crystalline polymers are prepared by, for example, applying a solution of a liquid crystalline polymer on an alignment surface such as those obtained by rubbing the surface of a thin film such as polyimide or polyvinyl alcohol formed on a glass plate, or by obliquely depositing silicon oxide. This is done by developing and heat treatment.

  The retardation plate may have an appropriate retardation according to the purpose of use, such as those for the purpose of compensating for various wavelength plates or birefringence of the liquid crystal layer, viewing angle, and the like. What laminated | stacked the phase difference plate and controlled optical characteristics, such as phase difference, etc. may be used.

  The elliptical polarizing plate and the reflective elliptical polarizing plate are obtained by laminating a polarizing plate or a reflective polarizing plate and a retardation plate in an appropriate combination. Such an elliptically polarizing plate or the like can also be formed by sequentially laminating them sequentially in the manufacturing process of the liquid crystal display device so as to be a combination of a (reflective) polarizing plate and a retardation plate. An optical member such as a polarizing plate has an advantage that it can improve the production efficiency of a liquid crystal display device and the like because of excellent quality stability and lamination workability.

  The viewing angle compensation film is a film for widening the viewing angle so that an image can be seen relatively clearly even when the screen of the liquid crystal display device is viewed from a slightly oblique direction rather than perpendicular to the screen. As such a viewing angle compensation phase difference plate, for example, a phase difference plate, an alignment film such as a liquid crystal polymer, or an alignment layer such as a liquid crystal polymer supported on a transparent substrate is used. A normal retardation plate uses a birefringent polymer film uniaxially stretched in the plane direction, whereas a retardation plate used as a viewing angle compensation film stretches biaxially in the plane direction. Birefringent polymer film, biaxially stretched film such as polymer with birefringence with a controlled refractive index in the thickness direction that is uniaxially stretched in the plane direction and stretched in the thickness direction, etc. Used. Examples of the inclined alignment film include a film obtained by bonding a heat shrink film to a polymer film and stretching or / and shrinking the polymer film under the action of the contraction force by heating, and a film obtained by obliquely aligning a liquid crystal polymer. Can be mentioned. The raw material polymer for the phase difference plate is the same as the polymer described in the previous phase difference plate, preventing coloration due to a change in the viewing angle based on the phase difference by the liquid crystal cell and expanding the viewing angle for good visual recognition. An appropriate one for the purpose can be used.

  Also, from the viewpoint of achieving a wide viewing angle with good visibility, an optically compensated phase difference in which a liquid crystal polymer alignment layer, in particular an optically anisotropic layer composed of a discotic liquid crystal polymer gradient alignment layer, is supported by a triacetylcellulose film. A plate can be preferably used.

  A polarizing plate obtained by bonding a polarizing plate and a brightness enhancement film is usually provided on the back side of a liquid crystal cell. The brightness enhancement film reflects a linearly polarized light with a predetermined polarization axis or a circularly polarized light in a predetermined direction when natural light is incident due to a backlight such as a liquid crystal display device or reflection from the back side, and transmits other light. In addition, a polarizing plate in which a brightness enhancement film is laminated with a polarizing plate allows light from a light source such as a backlight to enter to obtain transmitted light in a predetermined polarization state, and reflects light without transmitting the light other than the predetermined polarization state. The The light reflected on the surface of the brightness enhancement film is further inverted through a reflective layer or the like provided behind the brightness enhancement film and re-incident on the brightness enhancement film, and part or all of the light is transmitted as light having a predetermined polarization state. Luminance can be improved by increasing the amount of light transmitted through the enhancement film and increasing the amount of light that can be used for liquid crystal display image display or the like by supplying polarized light that is difficult to be absorbed by the polarizer. That is, when light is incident through the polarizer from the back side of the liquid crystal cell without using a brightness enhancement film, light having a polarization direction that does not coincide with the polarization axis of the polarizer is almost polarized. It is absorbed by the polarizer and does not pass through the polarizer. That is, although depending on the characteristics of the polarizer used, approximately 50% of the light is absorbed by the polarizer, and the amount of light that can be used for liquid crystal image display or the like is reduced accordingly, resulting in a dark image. The brightness enhancement film allows light having a polarization direction that is absorbed by the polarizer to be reflected once by the brightness enhancement film without being incident on the polarizer, and further inverted through a reflective layer provided on the rear side thereof. Repeatedly re-enter the brightness enhancement film, and the brightness enhancement film transmits only polarized light whose polarization direction is such that the polarization direction of light reflected and inverted between the two can pass through the polarizer. Therefore, light such as a backlight can be efficiently used for displaying an image on the liquid crystal display device, and the screen can be brightened.

  A diffusion plate may be provided between the brightness enhancement film and the reflective layer. The polarized light reflected by the brightness enhancement film is directed to the reflective layer or the like, but the installed diffuser plate uniformly diffuses the light passing therethrough and simultaneously cancels the polarized state and becomes a non-polarized state. That is, the diffuser plate returns the polarized light to the original natural light state. The light in the non-polarized state, that is, the natural light state is directed toward the reflection layer and the like, reflected through the reflection layer and the like, and again passes through the diffusion plate and reenters the brightness enhancement film. Thus, while maintaining the brightness of the display screen by providing a diffuser plate that returns polarized light to the original natural light state between the brightness enhancement film and the reflective layer, etc., the brightness unevenness of the display screen is reduced at the same time, A uniform and bright screen can be provided. By providing such a diffuser plate, it is considered that the first incident light has a moderate increase in the number of repetitions of reflection, and in combination with the diffusion function of the diffuser plate, a uniform bright display screen can be provided.

  The brightness enhancement film has a characteristic of transmitting linearly polarized light having a predetermined polarization axis and reflecting other light, such as a multilayer thin film of dielectric material or a multilayer laminate of thin film films having different refractive index anisotropies. Such as an alignment film of a cholesteric liquid crystal polymer or an alignment liquid crystal layer supported on a film substrate, which reflects either left-handed or right-handed circularly polarized light and transmits other light. Appropriate things, such as a thing, can be used.

  Therefore, in the brightness enhancement film of the type that transmits linearly polarized light having the predetermined polarization axis as described above, the transmitted light is incident on the polarizing plate with the polarization axis aligned as it is, thereby efficiently transmitting while suppressing absorption loss due to the polarizing plate. Can be made. On the other hand, in a brightness enhancement film of a type that emits circularly polarized light such as a cholesteric liquid crystal layer, it can be incident on a polarizer as it is, but from the viewpoint of suppressing absorption loss, the circularly polarized light is linearly polarized through a retardation plate. It is preferable to make it enter into a polarizing plate. Note that circularly polarized light can be converted to linearly polarized light by using a quarter wave plate as the retardation plate.

  A retardation plate that functions as a quarter-wave plate in a wide wavelength range such as a visible light region exhibits, for example, a retardation layer that functions as a quarter-wave plate for light-color light having a wavelength of 550 nm and other retardation characteristics. It can be obtained by a method of superposing a retardation layer, for example, a retardation layer functioning as a half-wave plate. Therefore, the retardation plate disposed between the polarizing plate and the brightness enhancement film may be composed of one or more retardation layers.

  In addition, the cholesteric liquid crystal layer can also be obtained by reflecting circularly polarized light in a wide wavelength range such as a visible light region by combining two or more layers having different reflection wavelengths and having an overlapping structure. Based on this, transmitted circularly polarized light in a wide wavelength range can be obtained.

  Further, the polarizing plate may be formed by laminating a polarizing plate and two or three or more optical layers like the above-described polarization separation type polarizing plate. Therefore, a reflective elliptical polarizing plate or a semi-transmissive elliptical polarizing plate in which the above-mentioned reflective polarizing plate or transflective polarizing plate and a retardation plate are combined may be used.

  The optical member in which the optical layer is laminated on the polarizing plate can be formed by a method of sequentially laminating separately in the manufacturing process of a liquid crystal display device or the like. There is an advantage that the manufacturing process of the liquid crystal display device and the like can be improved. For the lamination, an appropriate adhesive means such as an adhesive layer can be used. When adhering the polarizing plate and the other optical layer, their optical axes can be set at an appropriate arrangement angle in accordance with the target phase difference characteristic.

  In addition, each layer such as the optical member and the pressure-sensitive adhesive layer of the pressure-sensitive adhesive optical member of the present invention includes, for example, an ultraviolet ray such as a salicylic acid ester compound, a benzophenol compound, a benzotriazole compound, a cyanoacrylate compound, or a nickel complex compound. What gave the ultraviolet absorptivity by systems, such as a system processed with an absorber, may be used.

  The pressure-sensitive adhesive optical member of the present invention can be preferably used for forming various image display devices such as a liquid crystal display device. The liquid crystal display device can be formed according to the conventional method. That is, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell, an adhesive optical member, and an illumination system as necessary, and incorporating a drive circuit. There is no particular limitation except that an optical member is used. As the liquid crystal cell, any type such as a TN type, an STN type, or a π type can be used.

  An appropriate liquid crystal display device such as a liquid crystal display device in which an adhesive optical member is disposed on one side or both sides of a liquid crystal cell, or a backlight or a reflector used in an illumination system can be formed. In that case, the optical member by this invention can be installed in the one side or both sides of a liquid crystal cell. When optical members are provided on both sides, they may be the same or different. Further, when forming a liquid crystal display device, for example, a single layer or a suitable part such as a diffusing plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusing plate, a backlight, etc. Two or more layers can be arranged.

  Next, an organic electroluminescence device (organic EL display device) will be described. Generally, in an organic EL display device, a transparent electrode, an organic light emitting layer, and a metal electrode are sequentially laminated on a transparent substrate to form a light emitter (organic electroluminescent light emitter). Here, the organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative and the like and a light emitting layer made of a fluorescent organic solid such as anthracene, Alternatively, a structure having various combinations such as a laminate of such a light emitting layer and an electron injection layer composed of a perylene derivative or the like, or a laminate of these hole injection layer, light emitting layer, and electron injection layer is known. It has been.

  In organic EL display devices, holes and electrons are injected into the organic light-emitting layer by applying a voltage to the transparent electrode and the metal electrode, and the energy generated by recombination of these holes and electrons excites the phosphor material. Then, light is emitted on the principle that the excited fluorescent material emits light when returning to the ground state. The mechanism of recombination in the middle is the same as that of a general diode, and as can be predicted from this, the current and the emission intensity show strong nonlinearity with rectification with respect to the applied voltage.

  In an organic EL display device, in order to extract light emitted from the organic light emitting layer, at least one of the electrodes must be transparent, and a transparent electrode usually formed of a transparent conductor such as indium tin oxide (ITO) is used as an anode. It is used as. On the other hand, in order to facilitate electron injection and increase luminous efficiency, it is important to use a material having a small work function for the cathode, and usually metal electrodes such as Mg—Ag and Al—Li are used.

  In the organic EL display device having such a configuration, the organic light emitting layer is formed of a very thin film having a thickness of about 10 nm. For this reason, the organic light emitting layer transmits light almost completely like the transparent electrode. As a result, light that is incident from the surface of the transparent substrate at the time of non-light emission, passes through the transparent electrode and the organic light emitting layer, and is reflected by the metal electrode is again emitted to the surface side of the transparent substrate. The display surface of the organic EL display device looks like a mirror surface.

  In an organic EL display device comprising an organic electroluminescent light emitting device comprising a transparent electrode on the surface side of an organic light emitting layer that emits light upon application of a voltage and a metal electrode on the back side of the organic light emitting layer, the surface of the transparent electrode While providing a polarizing plate on the side, a retardation plate can be provided between the transparent electrode and the polarizing plate.

  Since the retardation plate and the polarizing plate have a function of polarizing light incident from the outside and reflected by the metal electrode, there is an effect that the mirror surface of the metal electrode is not visually recognized by the polarization action. In particular, the mirror surface of the metal electrode can be completely shielded by configuring the retardation plate with a quarter-wave plate and adjusting the angle formed by the polarization direction of the polarizing plate and the retardation plate to π / 4. .

  That is, only the linearly polarized light component of the external light incident on the organic EL display device is transmitted by the polarizing plate. This linearly polarized light becomes generally elliptically polarized light by the phase difference plate, but becomes circularly polarized light especially when the phase difference plate is a quarter wave plate and the angle between the polarization direction of the polarizing plate and the phase difference plate is π / 4. .

  This circularly polarized light is transmitted through the transparent substrate, the transparent electrode, and the organic thin film, is reflected by the metal electrode, is again transmitted through the organic thin film, the transparent electrode, and the transparent substrate, and becomes linearly polarized light again on the retardation plate. And since this linearly polarized light is orthogonal to the polarization direction of a polarizing plate, it cannot permeate | transmit a polarizing plate. As a result, the mirror surface of the metal electrode can be completely shielded.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In addition, all the parts and% in each example are based on weight.

(Measurement of weight average molecular weight)
The weight average molecular weight of the produced (meth) acrylic polymer was measured by GPC (gel permeation chromatography) and converted by standard polystyrene.
GPC device: manufactured by Tosoh Corporation, HLC-8120GPC
Column: manufactured by Tosoh Corporation, G7000H _XL + GMH _XL + GMH _XL
Column size: 7.8 mmφ × 30 cm × 3 (total 90 cm)
Flow rate: 0.8ml / min
Concentration: 0.1 wt%
Injection volume: 100 μl
Column temperature: 40 ° C
Eluent: THF
Detector: Differential refractometer

(Measurement of content of polymer component having a molecular weight of 100,000 or less)
The content of the polymer component having a molecular weight of 100,000 or less was calculated from the GPC measurement result using a data processing device (GPC-8020, manufactured by Tosoh Corporation). However, the monomer component was excluded.

(Measurement of viscosity of pressure-sensitive adhesive composition for optical members)
The viscosity of the pressure-sensitive adhesive composition for optical members was measured under the following conditions using a TV-20 viscometer spindle type (Toki Sangyo Co., Ltd.).
Rotor: THH-14
Rotation speed: 10rpm
Shear rate: 2.5 / s
Measurement temperature: 23 ° C

(Coating property evaluation of pressure-sensitive adhesive composition for optical members)
The coating property of the pressure-sensitive adhesive composition for optical members was evaluated by viscosity and surface uniformity. The evaluation results are shown in Table 1.
Viscosity: In the above viscosity measurement, the case of less than 10000 mPa · s was evaluated as “good” and the case of 10000 mPa · s or more was evaluated as “x” (bad).
Surface uniformity: In the case of coating, the case where no polymer was precipitated and a uniform coated surface could be formed was evaluated as ◯, and the case where the polymer was deposited and a uniform coated surface could not be formed was evaluated as x.

(Durability evaluation of adhesive optical members)
The obtained adhesive optical member (15 inch size, 240 × 320 mm) was attached to non-alkali glass (Corning 1737, 250 × 350 mm, thickness 0.7 mm) to prepare a sample. The sample was stored in an autoclave at 50 ° C. and 0.5 MPa for 15 minutes. Thereafter, the sample was stored in an environment of 80 ° C. for 500 hours, and further stored in an environment of 60 ° C. and 90% RH for 500 hours. Then, durability evaluation of the adhesion type optical member was performed on the following reference | standard using this sample. The evaluation results are shown in Table 1.
○: There is no peeling or floating of the optical member.
X: There is peeling or floating of the optical member.

Example 1
(Preparation of pressure-sensitive adhesive composition for optical members)
70 parts of butyl acrylate, 25 parts of 2-ethylhexyl acrylate, 5 parts of acrylic acid, 0.08 part of 2-hydroxyethyl acrylate, 0.1 part of 2,2-azobisisobutyronitrile, and 160 parts of ethyl acetate After putting into a four-necked flask equipped with a nitrogen introduction tube and a cooling tube and sufficiently purging with nitrogen, a polymerization reaction was carried out at 55 ° C. for 10 hours with stirring under a nitrogen stream, and a weight average molecular weight of 2.2 million and a molecular weight of 100,000 The solution (1) (solid content concentration: 37 weight%) containing the acrylic polymer whose content rate of the following polymer components is 2 weight% was obtained.

  In this solution (1), 327.3 parts of heptane (solubility parameter: 7.3), 27.3 parts of toluene (solubility parameter: 8.9), and 30.9 parts of ethyl acetate (solubility parameter: 9.1) were added. In addition, a solution (2) (solid content concentration: 15% by weight) was obtained. The content of the hydrocarbon solvent A (heptane) in the solution (2) is 60% of the total organic solvent, and the content of the high boiling point high solubility solvent B (toluene) is 5% of the total organic solvent. .

Polyisocyanate-based crosslinking agent 0 comprising 0.1 part of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent and a tolylene diisocyanate adduct of trimethylolpropane with respect to 100 parts of polymer solids of the solution (2) .5 parts was added to the solution (2) and mixed uniformly to prepare a pressure-sensitive adhesive composition a for optical members.
(Creation of adhesive optical member)
The pressure-sensitive adhesive composition a was applied to a polyethylene terephthalate film (thickness: 38 μm) subjected to silicone release treatment so that the thickness after drying was 25 μm, and heated at 140 ° C. for 2 minutes to be a pressure-sensitive adhesive layer for optical members Formed. The pressure-sensitive adhesive layer for an optical member was bonded to a polarizing plate to prepare an adhesive optical member.

Example 2
(Preparation of pressure-sensitive adhesive composition for optical members)
245.5 parts of heptane, 109.1 parts of toluene, and 30.9 parts of ethyl acetate were added to the solution (1) to obtain a solution (3) (solid content concentration: 15% by weight). The content of the hydrocarbon solvent A (heptane) in the solution (3) is 45% of the total organic solvent, and the content of the high boiling point high solubility solvent B (toluene) is 20% of the total organic solvent. .

Polyisocyanate-based crosslinking agent 0 comprising 0.1 part of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent and a tolylene diisocyanate adduct of trimethylolpropane with respect to 100 parts of polymer solids of the solution (3) .5 parts was added to the solution (3) and mixed uniformly to prepare an optical member pressure-sensitive adhesive composition b.
(Creation of adhesive optical member)
An adhesive optical member was prepared in the same manner as in Example 1 except that the optical member adhesive composition b was used.

Example 3
(Preparation of pressure-sensitive adhesive composition for optical members)
190.9 parts of heptane, 27.3 parts of toluene, and 30.9 parts of ethyl acetate were added to the solution (1) to obtain a solution (4) (solid content concentration: 15% by weight). The content of the hydrocarbon solvent A (heptane) in the solution (4) is 35% of the total organic solvent, and the content of the high boiling point high solubility solvent B (toluene) is 5% of the total organic solvent. .

Polyisocyanate-based crosslinking agent 0 comprising 0.1 part of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent and a tolylene diisocyanate adduct of trimethylolpropane with respect to 100 parts of polymer solids of the solution (4) .5 parts was added to the solution (4) and mixed uniformly to prepare an optical member pressure-sensitive adhesive composition c.
(Creation of adhesive optical member)
An adhesive optical member was prepared in the same manner as in Example 1 except that the optical member adhesive composition c was used.

Example 4
(Preparation of pressure-sensitive adhesive composition for optical members)
To the solution (1), 109.1 parts of heptane, 245.5 parts of toluene, and 30.9 parts of ethyl acetate were added to obtain a solution (5) (solid content concentration: 15% by weight). The content of the hydrocarbon solvent A (heptane) in the solution (5) is 20% of the total organic solvent, and the content of the high boiling point high solubility solvent B (toluene) is 45% of the total organic solvent. .

Polyisocyanate-based crosslinking agent 0 comprising 0.1 part of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent and a tolylene diisocyanate adduct of trimethylolpropane with respect to 100 parts of the polymer solid content of the solution (5) 0 .5 parts was added to the solution (5) and mixed uniformly to prepare an optical member pressure-sensitive adhesive composition d.
(Creation of adhesive optical member)
A pressure-sensitive adhesive optical member was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive composition d for optical members was used.

Example 5
(Preparation of pressure-sensitive adhesive composition for optical members)
245.5 parts of hexane (solubility parameter: 7.3), 109.1 parts of toluene, and 30.9 parts of ethyl acetate are added to the solution (1) to obtain a solution (6) (solid content concentration: 15% by weight). Obtained. The content of the hydrocarbon solvent A (hexane) in the solution (6) is 45% of the total organic solvent, and the content of the high boiling point high solubility solvent B (ethyl acetate + toluene) is 55% of the total organic solvent. %.

Polyisocyanate-based crosslinking agent 0 comprising 0.1 part of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent and a tolylene diisocyanate adduct of trimethylolpropane with respect to 100 parts of the polymer solid content of the solution (6) .5 parts was added to the solution (6) and mixed uniformly to prepare an optical member pressure-sensitive adhesive composition e.
(Creation of adhesive optical member)
A pressure-sensitive adhesive optical member was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive composition e for optical members was used.

Example 6
(Preparation of pressure-sensitive adhesive composition for optical members)
245.5 parts of Cactus solvent (manufactured by Japan Energy), 109.1 parts of toluene, and 30.9 parts of ethyl acetate are added to the solution (1) to obtain a solution (7) (solid content concentration: 15% by weight). It was. The content of the hydrocarbon solvent A (Cactus solvent) in the solution (7) is 45% of the total organic solvent, and the content of the high-boiling and highly soluble solvent B (toluene) is 20% of the total organic solvent. is there.

Polyisocyanate-based crosslinking agent 0 comprising 0.1 part of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent and a tolylene diisocyanate adduct of trimethylolpropane with respect to 100 parts of polymer solids of the solution (7) .5 parts was added to the solution (7) and mixed uniformly to prepare a pressure-sensitive adhesive composition f for optical members.
(Creation of adhesive optical member)
A pressure-sensitive adhesive optical member was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive composition f for optical members was used.

Example 7
(Preparation of pressure-sensitive adhesive composition for optical members)
100 parts of butyl acrylate, 5 parts of acrylic acid, 0.07 part of 2-hydroxyethyl acrylate, 0.2 part of dibenzoyl peroxide and 160 parts of ethyl acetate are put into a four-necked flask equipped with a nitrogen introduction tube and a cooling tube. Then, after sufficiently purging with nitrogen, a polymerization reaction is carried out at 58 ° C. for 10 hours with stirring under a nitrogen stream, and the content of the polymer component having a weight average molecular weight of 2 million and a molecular weight of 100,000 or less is 2% by weight. A solution (8) containing polymer (solid content concentration: 37% by weight) was obtained.

  250.5 parts of heptane, 111.3 parts of toluene, and 34.8 parts of ethyl acetate were added to the solution (8) to obtain a solution (9) (solid content concentration: 15% by weight). The content of the hydrocarbon solvent A (heptane) in the solution (9) is 45% of the total organic solvent, and the content of the high boiling point high solubility solvent B (toluene) is 20% of the total organic solvent. .

Polyisocyanate-based crosslinking agent 0 comprising 0.075 part of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent and a tolylene diisocyanate adduct of trimethylolpropane with respect to 100 parts of polymer solids of the solution (9) .6 parts was added to the solution (9) and mixed uniformly to prepare a pressure-sensitive adhesive composition g for optical members.
(Creation of adhesive optical member)
An adhesive optical member was prepared in the same manner as in Example 1 except that the above adhesive composition g for optical members was used.

Comparative Example 1
(Preparation of pressure-sensitive adhesive composition for optical members)
546 parts of ethyl acetate was added to the solution (1) to obtain a solution (10) (solid content concentration: 12% by weight).

Polyisocyanate-based cross-linking agent comprising 0.1 part of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent and a tolylene diisocyanate adduct of trimethylolpropane with respect to 100 parts of polymer solids of the solution (10) 0 .5 parts was added to the solution (10) and mixed uniformly to prepare an optical member pressure-sensitive adhesive composition h.
(Creation of adhesive optical member)
An adhesive optical member was prepared in the same manner as in Example 1 except that the optical member pressure-sensitive adhesive composition h was used.

Comparative Example 2
(Preparation of pressure-sensitive adhesive composition for optical members)
385.5 parts of ethyl acetate was added to the solution (1) to obtain a solution (11) (solid content concentration: 15% by weight).

Polyisocyanate-based crosslinking agent 0 comprising 0.1 part of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent and a tolylene diisocyanate adduct of trimethylolpropane with respect to 100 parts of polymer solids of the solution (11) .5 parts was added to the solution (11) and mixed uniformly to prepare an optical member pressure-sensitive adhesive composition i.
(Creation of adhesive optical member)
A pressure-sensitive adhesive optical member was prepared in the same manner as in Example 1 except that the above-mentioned pressure-sensitive adhesive composition i for optical members was used.

Comparative Example 3
(Preparation of pressure-sensitive adhesive composition for optical members)
To the solution (1), 354.6 parts of heptane, 27.3 parts of toluene, and 3.7 parts of ethyl acetate were added to obtain a solution (12) (solid content concentration: 15% by weight). The content of the hydrocarbon solvent A (heptane) in the solution (12) is 65% of the total organic solvent, and the content of the high boiling point high solubility solvent B (toluene) is 5% of the total organic solvent. .

Polyisocyanate-based crosslinking agent 0 comprising 0.1 part of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent and a tolylene diisocyanate adduct of trimethylolpropane with respect to 100 parts of polymer solids of the solution (12) .5 parts was added to the solution (12) and mixed uniformly to prepare an optical member pressure-sensitive adhesive composition j.
(Creation of adhesive optical member)
A pressure-sensitive adhesive optical member was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive composition j for optical members was used.

Comparative Example 4
(Preparation of pressure-sensitive adhesive composition for optical members)
327.3 parts of heptane and 58.2 parts of ethyl acetate were added to the solution (1) to obtain a solution (13) (solid content concentration: 15% by weight). The content of the hydrocarbon solvent A (heptane) in the solution (13) is 60% of the total organic solvent.

Polyisocyanate-based crosslinking agent 0 comprising 0.1 part of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent and a tolylene diisocyanate adduct of trimethylolpropane with respect to 100 parts of polymer solids of the solution (13) .5 parts was added to the solution (13) and mixed uniformly to prepare an optical member pressure-sensitive adhesive composition k.
(Creation of adhesive optical member)
A pressure-sensitive adhesive optical member was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive composition k for optical members was used.

Comparative Example 5
(Preparation of pressure-sensitive adhesive composition for optical members)
To the solution (1), 54.6 parts of heptane, 109.1 parts of toluene, and 221.9 parts of ethyl acetate were added to obtain a solution (14) (solid content concentration: 15% by weight). The content of the hydrocarbon solvent A (heptane) in the solution (14) is 10% of the total organic solvent, and the content of the high boiling point high solubility solvent B (toluene) is 20% of the total organic solvent. .

Polyisocyanate-based crosslinking agent 0 comprising 0.1 part of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent and a tolylene diisocyanate adduct of trimethylolpropane with respect to 100 parts of polymer solids of the solution (14) .5 parts was added to the solution (14) and mixed uniformly to prepare an optical member pressure-sensitive adhesive composition l.
(Creation of adhesive optical member)
A pressure-sensitive adhesive optical member was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive composition 1 for optical members was used.

Comparative Example 6
(Preparation of pressure-sensitive adhesive composition for optical members)
To the solution (1), 245.5 parts of decane (solubility parameter: 6.6), 109.1 parts of toluene, and 30.9 parts of ethyl acetate were added to obtain a solution (15) (solid content concentration: 15% by weight). Obtained. The decane content in the solution (15) is 45% of the total organic solvent.

Polyisocyanate-based crosslinking agent 0 comprising 0.1 part of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent and a tolylene diisocyanate adduct of trimethylolpropane with respect to 100 parts of polymer solids of the solution (15) .5 parts was added to the solution (15) and mixed uniformly to prepare an optical member pressure-sensitive adhesive composition m.
(Creation of adhesive optical member)
A pressure-sensitive adhesive optical member was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive composition m for optical members was used.

Comparative Example 7
396.6 parts of ethyl acetate was added to the solution (8) to obtain a solution (16) (solid content concentration: 15% by weight).

Polyisocyanate-based crosslinking agent 0 comprising 0.1 part of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent and a tolylene diisocyanate adduct of trimethylolpropane with respect to 100 parts of polymer solids of the solution (16) .5 parts was added to the solution (16) and mixed uniformly to prepare an optical member pressure-sensitive adhesive composition n.
(Creation of adhesive optical member)
A pressure-sensitive adhesive optical member was prepared in the same manner as in Example 1 except that the pressure-sensitive adhesive composition n for optical members was used.

表１から明らかなように、実施例１〜７では、有機溶媒の使用量削減が可能になり、塗工性に優れる光学部材用粘着剤組成物が得られる。また、該光学部材用粘着剤組成物から形成される粘着剤層は、耐久性及び表面均一性に優れることがわかる。

As is clear from Table 1, in Examples 1 to 7, the amount of the organic solvent used can be reduced, and a pressure-sensitive adhesive composition for an optical member having excellent coating properties can be obtained. Moreover, it turns out that the adhesive layer formed from this adhesive composition for optical members is excellent in durability and surface uniformity.

Claims (7)

(Meth) acrylic polymer, of 6 to 9 carbon atoms aliphatic hydrocarbon solvent (A), and the aliphatic boiling point than high hydrocarbon solvent and than said aliphatic hydrocarbon solvent (meth) acrylate A high-boiling and high-solubility solvent (B) having high solubility of the polymer, the content of the aliphatic hydrocarbon solvent (A) is 20 to 60% by weight of the total organic solvent, and Ratio of the content (% by weight) of the aliphatic hydrocarbon solvent (A) to the content (% by weight) of the high boiling point high solubility solvent (B) (high boiling point high solubility solvent (B) / aliphatic carbonization The adhesive composition for optical members whose hydrogen-based solvent (A)) is 0.05-4. The (meth) acrylic polymer contains 60% by weight or more of an alkyl acrylate having an alkyl group having 2 to 4 carbon atoms as a monomer, has a weight average molecular weight of 1,500,000 or more, and a molecular weight of 100,000 or less. The pressure-sensitive adhesive composition for an optical member according to claim 1, wherein the content of the component is 20% by weight or less. The pressure-sensitive adhesive composition for an optical member according to claim 2, wherein the (meth) acrylic polymer further contains 0.2 to 7% by weight of an unsaturated carboxylic acid as a monomer. The pressure-sensitive adhesive composition for an optical member according to any one of claims 1 to 3, comprising 0.01 to 1 part by weight of a silane coupling agent with respect to 100 parts by weight of the (meth) acrylic polymer. The pressure-sensitive adhesive composition for an optical member according to any one of claims 1 to 4, comprising 0.1 to 5 parts by weight of a crosslinking agent with respect to 100 parts by weight of the (meth) acrylic polymer. The manufacturing method of the adhesive layer for optical members which forms an adhesive layer using the adhesive composition for optical members in any one of Claims 1-5. The manufacturing method of the adhesive type optical member which forms an adhesive layer in the single side | surface or both surfaces of an optical member using the adhesive composition for optical members in any one of Claims 1-5.